1. Field of the Invention
The present invention relates to a sheet folding device that receives a sheet member (hereinafter, referred to simply as “sheet”) such as a transfer sheet or a recording paper and performs a predetermined sheet folding operation such as single folding or Z folding and an image forming apparatus with the sheet folding device.
2. Description of the Related Art
Japanese Patent No. 3812385 discloses a technique of adjusting a gradient of a folding position by separately moving transport path guide plates divided into two, front and rear ones and separately changing distances from a folding roller 53 to a stopper 49. Japanese Patent Application Laid-open No. 2003-81529 discloses a technique of tilting a folding roller according to a sheet.
In the case of the invention disclosed in Japanese Patent No. 3812385, since the transport distances at to a stop member become different between front and rear sides due to gradient adjustment of the folding position, the length of the folding position in a sheet transport direction is greatly influenced. Thus, at the same time when adjusting the gradient of the folding position, it is necessary to adjust the length of the folding position in the sheet transport direction. Further, since the whole guide plate is moved, the transport path shape is distorted in the front and rear sides, wrinkles may occur. Further, the number of components increases, and a complicated mechanism is required.
In the case of the invention disclosed in Japanese Patent Application Laid-open No. 2003-81529, since the folding roller is tilted according to the sheet, the number of components increases, and a mechanism is very complicated.